1. Field of the Invention
This invention relates to a seat belt retractor provided with a take-up force reducing mechanism.
1. Description of the Prior Art
The seat belt retractors of this type already proposed are of the construction in which use is made of a take-up spring of strong take-up force and a take-up spring of weak take-up force and during the wearing of the seat belt, the take-up action of the strong take-up spring is suppressed and only the weak take-up spring is caused to perform its take-up action, or of the construction in which a take-up spring and a spring acting in the opposite direction to the take-up spring are provided and during the wearing of the seat belt, the latter spring is caused to act to reduce the take-up force.
However, these retractors already proposed have a disadvantage that the construction of the change-over means for reducing the take-up force is complex, and also have a disadvantage that the range in which the take-up force can be reduced is limited.